In 1637, Pierre de Fermat scribbled a theorem in his copy of the ancient Greek text Arithmetica, writing “I have discovered a truly marvelous demonstration of this proposition that this margin is too narrow to contain.”

Google celebrates today with Fermat’s Last Theorem scribbled on a chalkboard. Mouse over the image and Google slyly jokes, “I have discovered a truly marvelous proof of this theorem, which this doodle is too small to contain.”

Despite the effort of countless mathematicians to solve the problem, no successful proof was published until 1995 by Andrew Wiles. In the meantime, the unsolved problem helped a few oh-so-important mathematic theories develop, such as the algebraic number theory and modularity theorem.